I. Field of the Invention
The present invention relates generally to point-to-multipoint communication systems and more particularly to a method and apparatus for providing group communication services in an existing communication system.
II. Description of the Related Art
Point-to-multipoint communication systems have been used for many years to provide communications generally between a central location and multiple users of the system. For example, dispatch systems using Land Mobile Radios (LMRs) have been used in trucks, taxis, buses, and other vehicles in order to communicate scheduling information between a central dispatch center and one or more corresponding fleet vehicles. Communications may be directed at a specific vehicle in the fleet or to all vehicles simultaneously.
Another example of a point-to-multipoint communication system is a wireless push-to-talk system. Such a system allows a group of individuals, each having a wireless telephone, to communicate with other members of the group. Typically, a push-to-talk system relies on a single frequency, or dedicated channel, over which communications are received by the wireless telephones. In most systems, only one member may transmit information to the other members at a time. However, all members can listen to the dedicated broadcast channel to receive communications from the single member who is transmitting. Members desiring to transmit to other members of the system typically send an access request by depressing a push-to-talk button on a respective communication device which allows sole access to the dedicated transmission channel.
Push-to-talk systems are typically used in outdoor settings where a group of geographically diverse people, or simply members, require communications with each other in a xe2x80x9cpoint-to-multipointxe2x80x9d fashion. Examples of push-to-talk system uses include workgroup communications, security communications, construction site communication, and localized military communications. The group of people requiring communications with each other is commonly known as a xe2x80x9cnet,xe2x80x9d each member of the net sometimes referred to as a xe2x80x9cnet member.xe2x80x9d
In a typical push-to-talk system, a dedicated channel, sometimes referred to as a broadcast channel, is used to transmit communications from one member to multiple other members of the net simultaneously. Generally, only one member may transmit voice information to the other member users at any given time. If another member attempts to transmit over the broadcast channel while another member is transmitting, interference between the two competing communications will occur, resulting in non-intelligible communications being received by the other net members.
In order to implement a push-to-talk communication system in a conventional wireless communication system, expensive modifications to the infrastructure are necessary. Presently, there exists today at least one wireless push-to-talk communication system which allows point-to-multipoint communications to take place by undertaking such modifications.
Besides the cost problem associated with current wireless point-to-multipoint communication systems is that, generally, communications are confined to members operating in relative close proximity to each other using the same technology to communicate with. In other words, the point-to-multipoint communications do not extend to other communication networks or technologies, such as the Public Switched Telephone Network (PSTN), to data networks, such as the Internet, or to satellite communication systems such as the GlobalStar satellite communication system.
The present invention is a system and method for providing group communication services in an existing communication system. In the exemplary embodiment, the present invention is implemented within an existing CDMA wireless communication system.
Point-to-multipoint communications are enabled in the present invention by converting real-time audio, real-time visual, and data, collectively referred to herein as media) into data packets in a communication device (CD). The data packets are produced in accordance with standard data protocols, for instance, the well-known TCP/IP Internet protocol. The media is transmitted using an air interface, or by other means, depending on what type of communication device is used, to a data network, typically the Internet.
A communications manager (CM) enables data packets from the data network to be distributed to various net members of each defined net. Thus, the addition of the CM enables group communications to a standard communication system which is not capable of group communications. The CM is a device which acts as a configurable switch, connecting communications from one user to one or more other users defined as a net. The CM is a data device, meaning that it sends and receives data packets, as defined by the particular data network to which it is connected. In one embodiment, the CM is connected directly to the Internet, allowing data packets to be routed between the CM and, ultimately, the CDs.
The CM allows users other than those in the wireless communication system to participate in group communications. For example, an audio-capable desktop computer located in an office or home could participate in group communications with one or more users of a terrestrial wireless communication system. Alternatively, or in addition, users of a satellite communication system can participate in group calls with members of the terrestrial wireless system, desktop users, or both. Information between these various communication devices, i.e. wireless phones, wireline phones, satellite telephones, paging devices, portable or desktop computers, digital cameras, video cameras, etc., is transmitted among net members over the data network, coordinated by the CM.
One advantage of the present invention over conventional wireless group communication systems is the ability to quickly and inexpensively implement the group communication system into an existing communication system which does not provide group communication services. For example, an IS-95 compliant CDMA wireless communication system can support group communications simply by the addition of the CM and point-to-multipoint compatible communication devices. Another advantage of the present invention is the ability for group communications to extend beyond the traditional boundaries of traditional wireless group communication systems. Using the present invention, users of a CDMA wireless communication system can engage in group communications with users of different communication devices and technologies.